Understanding delays in chronic limb-threatening ischaemia care: Application of the theoretical domains framework to identify factors affecting primary care clinicians' referral behaviours

INTRODUCTION

Patients in the community with suspected Chronic limb-threatening ischaemia (CLTI) should be urgently referred to vascular services for investigation and management. The Theoretical Domains Framework (TDF) allows identification of influences on health professional behaviour in order to inform future interventions. Here, the TDF is used to explore primary care clinicians' behaviours with regards to recognition and referral of CLTI.

METHODS

Semi-structured interviews were conducted with 20 podiatrists, nurses and general practitioners in primary care. Directed content analysis was performed according to the framework method. Utterances were coded to TDF domains, and belief statements were defined by grouping similar utterances. Relevance of domains was confirmed according to belief frequency, presence of conflicting beliefs and the content of the beliefs indicating relevance.

RESULTS

Nine TDF domains were identified as relevant to primary care clinicians: Knowledge, Environmental context and resources, Memory, Decision and attention processes, Beliefs about capabilities, Skills, Emotions, Reinforcement and Behavioural regulation. Relationships across domains were identified, including how primary care clinician confidence and working in a highly pressurized environment can affect behaviour.

CONCLUSION

We have identified key barriers and enablers to timely recognition and referral behaviour. These beliefs identify targets for theory-driven behaviour change interventions to reduce delays in CLTI pathways.

The symptom to assessment pathway for suspected chronic limb-threatening ischaemia (CLTI) affects quality of care: a process mapping exercise

BACKGROUND

Delays in the pathway from first symptom to treatment of chronic limb-threatening ischaemia (CLTI) are associated with worse mortality and limb loss outcomes. This study examined the processes used by vascular services to provide urgent care to patients with suspected CLTI referred from the community.

METHODS

Vascular surgery units from various regions in England were invited to participate in a process mapping exercise. Clinical and non-clinical staff at participating units were interviewed, and process maps were created that captured key staff and structures used to create processes for referral receipt, triage and assessment at the units.

RESULTS

Twelve vascular units participated, and process maps were created after interviews with 45 participants. The units offered multiple points of access for urgent referrals from general practitioners and other community clinicians. Triage processes were varied, with units using different mixes of staff (including medical staff, podiatrists and s) and this led to processes of varying speed. The organisation of clinics to provide slots for 'urgent' patients was also varied, with some adopting hot clinics, while others used dedicated slots in routine clinics. Service organisation could be further complicated by separate processes for patients with and without diabetes, and because of the organisation of services regionally into vascular networks that had arterial and non-arterial centres.

CONCLUSIONS

For referred patients with symptoms of CLTI, the points of access, triage and assessment processes used by vascular units are diverse. This reflects the local context and ingenuity of vascular units but can lead to complex processes. It is likely that benefits might be gained from simplification.

Influence of cardiometabolic medications on abdominal aortic aneurysm growth in the UK Aneurysm Growth Study: metformin and angiotensin-converting enzyme inhibitors associated with slower aneurysm growth

BACKGROUND

There is a clinical need for treatments that can slow or prevent the growth of an abdominal aortic aneurysm, not only to reduce the need for surgery, but to provide a means to treat those who cannot undergo surgery.

METHODS

Analysis of the UK Aneurysm Growth Study (UKAGS) prospective cohort was conducted to test for an association between cardiometabolic medications and the growth of an abdominal aortic aneurysm above 30 mm in diameter, using linear mixed-effect models.

RESULTS

A total of 3670 male participants with data available on abdominal aortic aneurysm growth, smoking status, co-morbidities, and medication history were included. The mean age at recruitment was 69.5 years, the median number of surveillance scans was 6, and the mean(s.e.) unadjusted abdominal aortic aneurysm growth rate was 1.75(0.03) mm/year. In a multivariate linear mixed-effect model, smoking (mean(s.e.) +0.305(0.07) mm/year, P = 0.00003) and antiplatelet use (mean(s.e.) +0.235(0.06) mm/year, P = 0.00018) were found to be associated with more rapid abdominal aortic aneurysm growth, whilst metformin was strongly associated with slower abdominal aortic aneurysm growth (mean(s.e.) -0.38(0.1) mm/year, P = 0.00019), as were angiotensin-converting enzyme inhibitors (mean(s.e.) -0.243(0.07) mm/year, P = 0.0004), angiotensin II receptor antagonists (mean(s.e.) -0.253(0.08) mm/year, P = 0.00255), and thiazides/related diuretics (mean(s.e.) -0.307(0.09) mm/year, P = 0.00078).

CONCLUSION

The strong association of metformin with slower abdominal aortic aneurysm growth highlights the importance of the ongoing clinical trials assessing the effectiveness of metformin with regard to the prevention of abdominal aortic aneurysm growth and/or rupture. The association of angiotensin-converting enzyme inhibitors, angiotensin II receptor antagonists, and diuretics with slower abdominal aortic aneurysm growth points to the possibility that optimization of cardiovascular risk management as part of abdominal aortic aneurysm surveillance may have the secondary benefit of also reducing abdominal aortic aneurysm growth rates.

Outcomes after minor lower limb amputation for peripheral arterial disease and diabetes: population-based cohort study

BACKGROUND

Patients with diabetes and peripheral arterial disease are at increased risk of minor amputation. The aim of study was to assess the rate of re-amputations and death after an initial minor amputation, and to identify associated risk factors.

METHODS

Data on all patients aged 40 years and over with diabetes and/or peripheral arterial disease, who underwent minor amputation between January 2014 and December 2018, were extracted from Hospital Episode Statistics. Patients who had bilateral index procedures or an amputation in the 3 years before the study were excluded. Primary outcomes were ipsilateral major amputation and death after the index minor amputation. Secondary outcomes were ipsilateral minor re-amputations, and contralateral minor and major amputations.

RESULTS

In this study of 22 118 patients, 16 808 (76.0 per cent) were men and 18 473 (83.5 per cent) had diabetes. At 1 year after minor amputation, the estimated ipsilateral major amputation rate was 10.7 (95 per cent c.i. 10.3 to 11.1) per cent. Factors associated with a higher risk of ipsilateral major amputation included male sex, severe frailty, diagnosis of gangrene, emergency admission, foot amputation (compared with toe amputation), and previous or concurrent revascularization. The estimated mortality rate was 17.2 (16.7 to 17.7) per cent at 1 year and 49.4 (48.6 to 50.1) per cent at 5 years after minor amputation. Older age, severe frailty, comorbidity, gangrene, and emergency admission were associated with a significantly higher mortality risk.

CONCLUSION

Minor amputations were associated with a high risk of major amputation and death. One in 10 patients had an ipsilateral major amputation within the first year after minor amputation and half had died by 5 years.

Identifying the research priorities of healthcare professionals in UK vascular surgery: modified Delphi approach

Background

The Vascular Research Collaborative was established to develop a national research strategy for patients with vascular disease in the UK. This project aimed to establish national research priorities in this patient group.

Methods

A modified Delphi approach, an established method for reaching a consensus opinion among a group of experts in a particular field, was used to survey national multidisciplinary vascular clinical specialists. Two rounds of online surveys were conducted involving the membership of the Vascular Society, Society of Vascular Nurses, Society for Vascular Technology, and the Rouleaux Club (vascular surgical trainees). The first round invited any suggestions for vascular research topics. A steering group then collated and rationalized the suggestions, categorizing them by consensus into pathological topics and research categories, and amalgamating the various questions relating to the same fundamental issue into a single question. The second round involved recirculating these questions to the same participants for priority scoring.

Results

Round 1 resulted in 1231 suggested research questions from 481 respondents. Steering group collation and rationalization resulted in 83 questions for ranking in round 2. The second round resulted in a hierarchical list of vascular research priorities. The highest scoring priorities addressed topics related to critical lower-limb ischaemia, diabetic foot disease, amputation, wound healing, carotid plaque morphology, and service organization/delivery.

Conclusion

It is anticipated that these results will drive the UK national vascular research agenda for the next 5–10 years. It will facilitate focused development and funding of new research projects in current clinical areas of unmet need where potential impact is greatest.

VEGF-A isoforms program differential VEGFR2 signal transduction, trafficking and proteolysis

Vascular endothelial growth factor A (VEGF-A) binding to the receptor tyrosine kinase VEGFR2 triggers multiple signal transduction pathways, which regulate endothelial cell responses that control vascular development. Multiple isoforms of VEGF-A can elicit differential signal transduction and endothelial responses. However, it is unclear how such cellular responses are controlled by isoform-specific VEGF-A-VEGFR2 complexes. Increasingly, there is the realization that the membrane trafficking of receptor-ligand complexes influences signal transduction and protein turnover. By building on these concepts, our study shows for the first time that three different VEGF-A isoforms (VEGF-A165, VEGF-A121 and VEGF-A145) promote distinct patterns of VEGFR2 endocytosis for delivery into early endosomes. This differential VEGFR2 endocytosis and trafficking is linked to VEGF-A isoform-specific signal transduction events. Disruption of clathrin-dependent endocytosis blocked VEGF-A isoform-specific VEGFR2 activation, signal transduction and caused substantial depletion in membrane-bound VEGFR1 and VEGFR2 levels. Furthermore, such VEGF-A isoforms promoted differential patterns of VEGFR2 ubiquitylation, proteolysis and terminal degradation. Our study now provides novel insights into how different VEGF-A isoforms can bind the same receptor tyrosine kinase and elicit diverse cellular outcomes.